With the advent of the 5G era, a wide variety of use cases are expected to make use of features such as enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communication (URLLC), and massive Machine Type Communications (mMTC). Differences in communication requirements for each use case make it important for communication service providers to build a wide variety of networks. In the initial period of the 5G era, many global communication service providers relied on a single vendor and integrated systems dominated the market, making it difficult for customers to construct flexible and agile networks in accordance with their needs. This concern has led to the emergence of a new movement called the Open Radio Access Network (Open RAN) to increase openness of the interface between devices with the aim of encouraging innovation by promoting competition among multiple vendors. In addition to NEC’s experience and know-how in communications, we will utilize our cloud computing technology that enables flexible and agile construction as well as our industrial know-how to build a strong ecosystem with partners who aim to promote openness together. This paper introduces NEC’s approach to increase adoption of Open RAN required in the 5G era.

Operators face growing energy consumption with an associated increase in OPEX, arising from the introduction of 5G and massive MIMO technology combined with the need to add capacity and densify networks to address the continuous growth in mobile network traffic. Added to this, many operators have set global sustainability goals to reduce carbon emissions in part achieved through managing energy consumption.
Data provided to GSMA from 7 Operators with 31 networks in 28 countries highlighted that 73% of network energy consumption is in the RAN with the Core Network, Data centers and Operations accounting for the remainder.
NEC has developed a fully automated software-based solution to address RAN energy consumption at cell and site level, through advanced algorithms and traffic prediction, enabling safe shutdown of excess site capacity during periods with low levels of user and data traffic, thereby reducing energy consumption. The solution incorporates intelligent continuous customer experience feedback enabling fast reactivation should traffic levels increase unexpectedly. It is applicable to both legacy and Open RAN based deployments.

Smart Surfaces, also known as Reconfigurable Intelligent Surfaces (RISs), are expected to play a crucial role to achieve the key performance indicators (KPIs) for future 6G networks. The revolutionary advantage of this novel and emerging technology relies in the ability to control the propagation environment by changing the traditional communication paradigm that perceives the communication channel as an uncontrollable black box. We present our RIS design that can efficiently alter the reflection angle of the impinging wave. Additionally, we overcome the need for a fast and complex control channel by introducing a Self-configuring Smart Surface that can be easily and seamlessly installed without requiring modifications of the deployed mobile network.

RAN virtualization will become a key technology for next-generation mobile networks. However, due to the computing fluctuations inherent to wireless dynamics and resource contention in shared computing infrastructure, the price to migrate from dedicated to shared platforms may be too high. We present Nuberu, a novel pipeline architecture for 4G/5G DUs specifically engineered for shared platforms. Nuberu has one objective to attain reliability: to guarantee a minimum set of signals that preserve synchronization between the DU and its users during computing capacity shortages and, provided this, maximize network throughput. To this end, we use techniques such as tight deadline control, jitter-absorbing buffers, predictive HARQ, and congestion control.

We present vrAIn, a resource orchestrator for vRANs based on deep reinforcement learning. First, we use an autoencoder to project high-dimensional context data into a latent representation. Then, we use a deep deterministic policy gradient (DDPG) algorithm based on an actor-critic neural network structure and a classifier to map contexts into resource control decisions. Our results show that: (i) vrAIn provides savings in computing capacity of up to 30% over CPU-agnostic methods; (ii) it improves the probability of meeting QoS targets by 25% over static policies; (iii) upon computing capacity under-provisioning, vrAIn improves throughput by 25% over stateof-the-art schemes; and (iv) it performs close to an optimal offline oracle.

NEC has one hundred and twenty-three years experiences and is maintaining the leading position in the networks and telecom radio technologies area. Now, NEC is one of the global frontier of O-RAN based mobile infrastructure equipment and network vendor. This paper introduces the NEC’s energy saving technologies development activities through the end to end O-RAN system which provide the operational benefits for the mobile operators and society by minimizing the energy consumption and carbon emission simultaneously responding to the explosive traffic demand growth with guarantee the user experienced QoS. In addition with a typical system configuration for the coverage assuming Japan island metro area, the estimated annual consumption reduction and OPEX cut and the carbon emission reduction using the proposed technologies have been shown as an example.

Millimeter-wave (mmW) communication is expected to provide high-speed data services in 5G (fifth-generation mobile communication system). Phased array antennas are essential for overcoming large path loss and less diffraction, and for utilizing mmW effectively. A low-cost and compact mmW phased array module integrating antennas and beamformer integration circuits (BFICs) is a key device for widespread use of mmW in 5G. This paper describes mmW phased-array transceiver implementation techniques including BFIC and antenna module. The BFIC employs area-efficient neutralized bi-directional technique which shares the circuit chain between TX and RX modes. Using the developed 28GHz BF ICs with 65-nm CMOS technology, the two types of phased array antenna modules, i.e., antenna on board (AoB) and antenna in package (AiP), are developed. A 64-element dual-polarized 28 GHz phased array AoB achieves a peak EIRP of 52.2 dBm and EVM of 3.2% at 64QAM for 5G NR. A 4-element phased array AiP with wafer level package (WLP) has an extremely low profile and high scalability applicable to various types of 5G devices.

We propose a radio-over-fiber (RoF) system with 1-bit outphasing modulation. The proposed RoF system does not require a power-hungry digital-to-analog converter in distributed antenna units and relaxes the operation speed of optical transceivers to reduce device cost. In the system, wide-band transmission with a signal bandwidth of 1 GHz was experimentally verified complying with the 3GPP standard for the adjacent channel leakage ratio (ACLR). Finally, the proposed RoF system has been shown to have a higher bandwidth efficiency compared with other systems. Therefore, the proposed RoF system provides a cost-effective in-building wireless solution for 5G and 6G mobile network systems.

This paper describes the experimental verifications of a 28 GHz multi-user massive distributed multiple-input multiple-output (MIMO) using comprehensive calibration without an additional transceiver path. A conventional massive collocated-MIMO using millimeter wave has low robustness in non-line of sight environments and restricts the number of simultaneously connected users due to the lack of propagation independent. The newly developed distributed MIMO system consists of the eight distributed active antennas connected to a digital and mixed signal processing unit. The proposed calibration for the distributed MIMO improves the pre-coding accuracy and enhances the number of simultaneously connected users and cell throughput. We demonstrate zero-forcing spatial multiplexing using up-link to down-link channel reciprocity for two, four, and six user equipment in an actual over-the-air office environment. The distributed MIMO shows high robustness in non-line of sight environments and a system throughput of 2.1 Gbps per 100 MHz for the sum of six simultaneous users.

The mainstays to increase cell throughput for the beyond 5G or later are multiple-input multiple-output (MIMO) techniques, the use of millimeter wave and sub-THz, and a modulation scheme. Orthogonal frequency-division multiplexing (OFDM) modulation, which is used for 4G and 5G, has high spectral efficiency and high robustness to multi-path fading channels. In contrast, OFDM has low robustness to time-varying channels for moving terminals, which is more important at millimeter wave and sub-THz transmission than for sub-6 GHz. This paper describes the experimental investigation of orthogonal time frequency space (OTFS) modulation using a 28 GHz multi-user distributed MIMO testbed in over-the-air and mobility environments. We measure OTFS and OFDM up-link signals with up to four user simultaneous connections using zero-forcing precoding. OTFS indicates higher robustness to time-variant channels than OFDM. The error vector magnitude and system throughput of OTFS are -22 dB and 1.9 Gbps with 100 MHz signal bandwidth, respectively. OTFS enables cell throughput enhancement for moving terminals in millimeter wave and sub-THz bands.

NEC has pursued spatial multiplexing performance with Massive MIMO by adopting full digital beamforming (BF) that can realize high spectrum efficiency in the commercial Sub6 GHz (less than 6GHz) band Massive Element Active Antenna System (AAS) for domestic and overseas 5G. Through NEC’S R&D activity, it has been found that Downlink (DL) SINR (Signal to Interference and Noise Ratio) to each user terminal (UT) deteriorated by the nonlinear distorted radiation caused by the power amplifier (PA) in transmitter (TX). Thus, NEC has confirmed that the use of Digital Predistortion (DPD) significantly improves DL SINR in high power region. And it has been also verified that the accuracy of nulls generated in each user terminal direction is determined by the residual amplitude and phase variation among all transceivers after calibration (CAL). Thus it was clarified that the double compensation of DPD and high-precision CAL is effective for achieving excellent spatial multiplexing performance by Massive MIMO.

This paper presents a newly developed realistic Doherty power amplifier (PA) design method with a black-box output combiner network. The method optimizes a realistic output network on the basis of ideal output network parameters with the black-box design by using the results of large-signal load-pull and S-parameter measurements without the need for transistor nonlinear models, which was required by the previous approach. The optimization considers main and auxiliary amplifier load modulations at back-off and peak output power levels. A 3.5 GHz 350 W Doherty PA with GaN-HEMT transistors is fabricated and measured to experimentally verify the method. The PA exhibits greater than 50% drain efficiency at 7 dB back-off and 57% peak drain efficiency at 6 dB back-off.

While large-scale multiple-input, multiple-output (Massive MIMO) system base stations have already been commercially deployed in the Sub6 GHz band in 5G (fifth-generation mobile communication system), similar deployments are expected in millimeter-wave base stations to support higher traffic capacity.
This paper describes the design and implementation of a 39 GHz 256-element hybrid active phased array antenna system with 16 individual digital transceivers and its wireless multi-user, multi-input, multi-output verification. The prototype is realized using a beamforming IC for 39 GHz antenna arrays based on a 65 nm CMOS process developed in collaboration with Tokyo Institute of Technology. Furthermore, a compact, high-density mounting method was studied, and a new 256-element array antenna module was developed by employing waveguide antennas to fully exploit millimeter-wave performance. Using the prototype, we conducted a multi-user MIMO (MU-MIMO) transmission test using zero-forced orthogonal multi-beam based on channel interoperability assuming an access link. As a result, an estimated total throughput of 2.42 Gbps according to 3GPP TS38.214 was achieved in 100 MHz band OFDM 8 MU-MIMO operation.

Communication networks such as the Internet have been widely used in recent decades in various fields such as business, education, and entertainment, and the challenge is to meet a diversity of needs and to solve social issues. To meet these challenges, the Open APN (All Photonic Network) is expected to be used to solve these issues from the viewpoints of high security, robustness, and power saving in addition to high capacity, low latency, and multi-connectivity. Now NEC is considering the photonic cloud as an example of participation in community activities, product development, and use cases. This paper introduces the trends in relevant community activities and NEC’s commitment to Open APNs.

NEC is accelerating its efforts to realize All Photonics Networks (APN), in which all communication infrastructure from the networks to terminals are built upon optical-based technologies. This paper discusses disaggregation (functional separation) and the open architecture of optical networks — which are crucial for APN — and introduces NEC’s SpectralWave WX series, a family of NEC’s first open specifications-compliant, open optical transport products.

Efforts to provide the open architecture for optical networks and All Photonics Networks (APN) are entering the stage where new value is created. This paper introduces NEC’s commitment to developing new value in the market such as the creation of an open ecosystem, integration to optimize the combination of open specification components, and case studies of field trials and other installations.

Innovative optical networks are essential for the implementation and acceleration of advanced information and communication services such as autonomous driving and telemedicine. NEC is working to implement an All Photonics Network (APN) that enables transmissions with a low latency, low power consumption, and high capacity and that also makes full use of optical technology. The APN needs flexible wavelength conversion that is both compact in size and economical. NEC is therefore conducting R&D on ultracompact, dual-wavelength, tunable lasers as laser sources to be the key to wavelength conversion in APNs and using silicon photonics (SiP) that have a high-density integration and mass-production capability. This paper provides a report on the wavelength conversion technology and the technologies for the SiP and wavelength tunable laser sources that can realize a dual-wavelength, tunable laser.

Communication traffic has been increasing rapidly in recent years and is expected to continue to grow exponentially in the future. While the capacity of backbone networks needs to be increased, there is also a growing trend toward openness where networks are constructed by flexibly selecting equipment without being bound to a specific vendor and another growing trend toward greenness where networks are designed to reduce power consumption to address concerns about environmental issues. This paper introduces NEC’s optical device technologies and product lines that support openness and greenness.

Data plane traffic in 5G mobile networks is expected to continue to grow rapidly in the future. Mobile communications providers face challenges in terms of location and power usage as they need to expand their facilities to accommodate this traffic. NEC is contributing to solutions by applying a variety of technologies to mobile networks. To preserve the global environment and pass it on to future generations, NEC is continually promoting R&D into carbon-neutral technologies and contributing to their implementation in society. This paper introduces some of the main technologies in this field.

5G (fifth-generation mobile communication system) defines network slicing technology that virtually separates the network layers. Network slicing makes it possible to provide use cases required for 5G — such as high speed and high capacity (eMBB), multiple connections (mMTC), and ultra-reliability and low latency (URLLC) — on a single network infrastructure. 5G is expected to solve a variety of social issues, and this paper introduces the network slicing technology developed by NEC that enables communications service providers to provide services promptly.

In recent years, expectations are rising for the realization of an affluent society by promoting digital transformation (DX) and high productivity through Beyond 5G, the Internet of Things (IoT), and artificial intelligence (AI). Against this backdrop, in addition to conventional policies of improving the average quality of service (QoS), there is an increasing need to strengthen policies that precisely adhere to ICT performance requirements per communication session and in real time to enable applications to be used with high performance (work speed, productivity, etc.) in a stable manner. This paper introduces an application-aware ICT control technology that enables the stable use of applications at high-performance levels.

With mobile traffic skyrocketing, telecom operators face the urgent need to scale their networks further while also aiming to curb investment costs and optimize network resource utilization. In this paper, we explore how using the public cloud as a key solution helps telecom operators meet this challenge. We present the essential technologies for maximizing the potential of the public cloud for 5G Core networks and introduce our initiatives to facilitate its implementation.

An enormous amount of network equipment, including base stations, is being deployed worldwide by communication service providers (CSPs). It is not unusual for a single CSP to have more than a million pieces of equipment — which are built, updated, broken down, and repaired on a daily basis and which are also supported day and night by a large number of staff involved in infrastructure maintenance. The operations of such network equipment are carried out by a group of systems called operating supporting systems (OSS). This paper introduces NEC’s next-generation OSS and orchestration products now being developed under the concept of autonomous networks with the aim of zero-touch operations by minimizing human contact and enabling networks to autonomously operate by themselves.

Networks are becoming more and more complex with the advancement of virtualization technology, and the increasing burden of operating these networks is becoming an issue. However, conventional automation methods, in which instructions on monitoring and handling methods are specified by using templates, are susceptible to alterations in network requirements themselves and require additional work hours for adjustment. Against this background, the technology used in autonomous operation — by which the entire process from network construction to operation is automated based on information on user requirements (or intent) — is attracting attention. NEC started conducting the R&D of the technology used in autonomous operations in 2017 and has been making pioneering efforts since then. This paper provides an overview of NEC’s technologies used in autonomous operations and its core automated design as well as an introduction to enhanced security support.

With the escalating frequency of cyberattacks targeting critical infrastructures, the safety of information and communications networks has emerged as a pressing concern. These networks not only serve as the foundation of these infrastructures but also present potential entry points for cyberattacks. Furthermore, with the implementation of the Economic Security Promotion Bill, operators of critical infrastructure are obligated to fulfill the responsibility of explaining the measures taken to uphold system security. This emphasizes the importance of ensuring transparency in IT systems, including network equipment, and maintaining ongoing awareness of their internal state. To address this challenge, NEC is actively engaged in the development of the Security Transparency Assurance Technology. In this paper, we highlight the importance of security transparency and delve into how NEC’s technology can be leveraged to ensure system security.

In recent years, the severity of threats in the cyberspace has intensified, raising concerns about the potential for significant economic and societal losses due to attacks targeting the security domain and supply chain of critical industrial infrastructure. At NEC, we ensure the provision of safe and secure network equipment by conducting inspections at our factories in Japan to address shipment and transportation risks, and by offering products that comprehensively collect and analyze equipment security information for managing risks during operation (this family of products is offered only in Japan). This paper outlines our initiatives to enhance supply chain management through secure manufacturing, inspections at our factories, and the utilization of NEC products designed to ensure secure operation.

As smartphones gain popularity, services such as map apps that use location information have become an essential part of people’s everyday lives. In recent years, location information has also begun to be used for a variety of purposes, such as autonomous driving, construction machinery, and drones. While the usage scenarios of location information vary, the demand for improved positioning technology is increasing. Against this background, NEC offers positioning solutions for communication service providers (CSPs) that achieve enhanced accuracy, reduced positioning time, and expanded coverage areas. This paper introduces NEC’s commitment to improving positioning technology and providing positioning systems for CSPs.

In light of growing environmental concerns and the introduction of 5G services, mobile operators face three significant challenges. These challenges involve dealing with packet congestion, reducing the total cost of ownership (TCO) in telecommunications facilities, and achieving carbon neutrality. To address the issue of packet congestion resulting from the high potential of 5G networks, the NEC Traffic Management Solution (TMS) provides an effective solution. By accurately predicting real-time data transmission volumes based on current transmission conditions, TMS effectively alleviates congestion. Under normal operating conditions, TMS maximizes the potential of 5G while improving the throughput degradation caused by concentrated user access and temporary congestion at specific times and locations. TMO also helps to reduce unnecessary data transmission, which not only helps minimize the TCO for telecommunications facilities but also aids in the pursuit of carbon neutrality objectives.

As digital transformation (DX) expands, growing attention is being directed towards private 5G (dedicated 5G networks in Japan hosted by entities outside the communication service sector is referred to as private 5G in this paper). While the use of radio waves has been exclusively restricted to mobile network operators so far, government authorities have recognized the need to attract private investment for effective use of radio resources and for the creation of social value. As a result, new players are entering the market. Because of the complexity of the technology and the high cost of system construction, however, it has been difficult to popularize this promising technology. To address this issue, NEC has now developed a private 5G system and managed services called UNIVERGE RV1200, which enables system construction at a reasonable price range. This paper introduces the features and usage scenarios of the NEC UNIVERGE RV1200.

NEC provides vertical services that combine industrial applications and networks such as 5G to promote the realization of digital transformation (DX) by improving labor shortages, increasing the efficiency of on-site work in the industrial sector, and other solutions. This paper introduces cases of vertical services using private 5G (dedicated 5G networks in Japan hosted by entities outside the communication service sector is referred to as private 5G in this paper) to support industrial DX as well as NEC CONNECT as an approach to achieve co-creation with partner companies.

The revision of guidelines from the Ministry of Internal Affairs and Communications and the Ministry of Health, Labour and Welfare have prompted local governments and hospitals to build private 5G (dedicated 5G networks in Japan hosted by entities outside the communication service sector is referred to as private 5G in this paper) networks on their existing infrastructure, aligning with these updates. Despite the increasing trend towards integration, the need to maintain network separation for security reasons persists. Therefore, it is imperative to implement network separation throughout the entire network, including the private 5G network, to ensure robust security measures are upheld. This paper aims to present a method for expanding virtual network technology, a widely embraced core component of NEC’s SDN solution, by integrating it with private 5G technology.

The spread of 5G has been enhancing the importance of networks. To fully unlock the potential of end-to-end 5G networks, not only the RAN domain but also the transport network needs to be advanced to align with the 5G era. Communication service providers (CSPs) are required to elevate their transport network to the next level by enhancing flexibility, agility, scalability, and prioritizing the increasingly important aspect of security, while maintaining the speed and capacity required in traditional transport networks as the most important KPIs. This paper introduces the NEC Value Added xHaul Solution Suite that addresses these challenges.

In the network domain operated by communication service providers (CSPs), there is a noticeable trend towards increased openness and a shift to multi-vendor networks, similar to the developments observed in the field of IT computing. With the emergence of these trends, the technical requirements for CSPs to deploy network components like IP routers and optical transport network equipment in their own transport network are becoming more complex. In this paper, keeping in mind these technology trends, we introduce NEC’s service portfolio, global organization, and case studies, by highlighting our expertise as a network system integrator in providing CSPs worldwide with best-of-breed solutions that are centered around consulting services and multi-vendor ecosystems.

As the importance of networks as social infrastructure grows, Communication Service Providers (CSPs) are focusing on automation solutions that can both accelerate the time to market and reduce operating costs. However, due to the complexities in terms of operation unique to the telecommunications industry, the introduction of automation has not progressed as smoothly as expected. The NEC xHaul Transport Automation Solution is composed of a multi-vendor ecosystem and services to deliver automation aimed at solving the variety of challenges that CSPs face when deploying automation solutions. This paper introduces the details of NEC’s xHaul Transport Automation Solution.

5G and Beyond 5G technology requires even higher capacity in transport networks. Transport networks in countries other than Japan have used fixed wireless systems as the mobile backhaul for ease of installation and TCO (total cost of ownership) reduction. But now that the standard specifications for cross-haul (xHaul) networks have been established, the application of fixed wireless systems is expected to expand as various 5G or Beyond 5G situations develop. This paper gives an outline of fixed wireless transport in the eras of 5G and Beyond 5G and also introduces the technologies and products supporting it.

5G and Beyond 5G networks require software-defined networking (SDN) and automation support for efficient use of wireless transport networks. Standardization bodies such as the ONF, IETF, and ETSI are promoting the standardization of device monitoring and control interfaces using the Network Configuration Protocol (NETCONF) and data models. By complying with these standards and cooperating with SDN orchestrators, NEC’s PASOLINK wireless transport devices and unified network management system (UNMS) provide automated solutions for the operation of wireless transport networks.

Microwave and millimeter-wave communication systems are used for mobile backhaul applications all over the world. The Beyond 5G and 6G applications, however, require a higher capacity of 50 Gbps or more, and this is difficult to achieve with conventional systems. This paper introduces the principles, features, challenges, and implementation methods of NEC’s OAM mode-multiplexing transmission system, which is a communication method suitable for high-frequency bands capable of increasing efficiency and capacity and for utilizing wider bandwidths. In a real-time transmission experiment conducted in the sub-terahertz band to demonstrate the feasibility of this technology, NEC succeeded in the transmission of 256QAM/16 multiplexing (14.7 Gbps) over 100m by combining it with polarization multiplexing. Now we aim to increase this to 100 Gbps for commercial release of this technology.

In this paper, we examine the worldview and image of the future society in the Beyond 5G era, which is expected to begin around 2030. We also look at NEC’s Beyond 5G vision, which considers changes in communications and the surrounding environment, expected role changes, and use cases. The direction of technological evolution that is considered necessary to achieve that vision, the key technology areas, and NEC’s initiatives for open innovation and ecosystem formation are also described.